Even Northern California’s wettest winter wasn’t enough to help the poor Delta smelt avoid dropping to another record low in 2017.

While the fingerlong fish might not seem of great consequence to most people, its health is a sign of the well-being of the Delta as a whole.

And the smelt are not well. Crews spent four months this fall using large nets to sample more than 100 sites from San Francisco Bay to the Delta. They caught a grand total of two fish.

That’s the worst showing in a survey that dates back to 1967. It’s also a 99.9 percent decline from the smelt’s highest estimated population level, measured in 1970.

“The population is so low that they can’t find each other to mate. We’re lucky to have any smelt,” said Tom Cannon, a fish ecologist and consultant for the Stockton-based environmental group California Sportfishing Protection Alliance.

The fish’s continued decline toward extinction might not be surprising if California was still stuck in a severe drought. But the Delta flooded last winter, and experts had been hoping the smelt might see at least a modest rebound as a result.

That’s what happened in 2011, another wet year, when the smelt population increased tenfold.

Not this time. Not only was there no rebound, but the number of fish found in the surveys actually declined slightly. It may be that there are so few smelt left that even four months of extensive surveying is not enough to detect increases or decreases in their numbers, said Peter Moyle, a University of California, Davis professor and expert on California’s native fishes.
A look at other species

Not all of the news is bad for Delta fish after a very wet 2017.

While a population index for the infamous Delta smelt declined from 8 to 2, the index for the striped bass — a valued sport fish — climbed from 124 to 470, the highest since 2001 (though still far lower than historic levels).

Longfin smelt, a cousin of the Delta smelt, rebounded nicely from 7 last year to 141 this year.

The index is not a measurement of the actual number of fish, but is calculated using a formula based on the number of fish found in surveys from September through December.

It’s also possible that last winter’s floods swept the smelt farther away from each other, making it even harder for the fish to find each other and breed, he said. Because they live for just one year, it’s critical that the species is able to reproduce annually.

“We really just don’t know what is going on with the smelt at this stage,” Moyle wrote in an email to The Record.

State and federal officials on Thursday said that some smelt likely did spawn successfully last spring, but that their offspring encountered problems later in the year, including an unusually hot summer that warmed water temperatures to lethal levels. This dry fall likely hasn’t helped, either.

“Things were going pretty well until the summer. Then the count dropped off,” said Carl Wilcox, a policy adviser with the state Department of Fish and Wildlife.

But environmentalists believe that water management actions have had a large role in the overall demise of the smelt, which could become the first Delta species in 60 years to go extinct.

Even in years with normal precipitation, so much water is taken upstream of the Delta or pumped directly to southland farms and cities that the estuary’s fish and wildlife face droughtlike conditions.

And while those water exports have sometimes been curtailed to protect the fish under the Endangered Species Act, those curtailments have not always been as aggressive as biologists recommended.

Smelt numbers really cratered during the most recent drought, when already-low flows were made even lower by state officials who decided to loosen water quality standards in the Delta so that more water could be stored in reservoirs. Even after the drought, earlier this fall, the U.S. Fish and Wildlife Agency agreed to temporarily relax another water quality rule to allow for more exports.

Agency spokesman Shane Hunt said Thursday that most recent “minor modification” likely had no effect on the smelt, which face a number of threats in addition to water withdrawals, such as pollution from farms and cities, and a loss of historic habitat.

But Doug Obegi, an attorney with the Natural Resources Defense Council in San Francisco, said the water policies of state and federal agencies over a number of years have caused cumulative harm to the species. And he’s not surprised at the latest dismal numbers.

“It’s the old death by a thousand cuts,” he said. “Even in years like this, when we should be providing better conditions for fish, the agencies still cut corners.”